As shown in FIG. 7(a), a conventional general substrate delivering robot 1A for delivering a thin plate-shaped substrate such as a semiconductor wafer or a liquid crystal glass substrate is constituted by a fixed base 2A, a first arm 3A coupled turnably to the fixed base 2A, a second arm 4A coupled turnably to the first arm 3A, and a fork 5A for substrate mounting which is turnably coupled to the second arm 4A. In the case in which such a substrate delivering robot can be caused to mount two substrates at the same time, the fork 5A having a central part turnably supported, one of ends provided with a processed substrate mounting section 5Aa for mounting a processed substrate and the other end provided with an unprocessed substrate mounting section 5Ab for mounting an unprocessed substrate is coupled turnably to the tip portion of the second arm 4A (for example, JP-A-7-142551).
In such a conventional substrate delivering robot capable of holding two substrates at the same time, however, one long fork is used. For this reason, there is a problem in that the minimum turning radius of the substrate delivering robot is large also in the contraction state of an arm, resulting in an increase in the installation area of the robot.